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Media Summary

For immediate release: November 15, 2010
Media Contact: NCHHSTP - News Media Line, +1-404-639-8895,

Session 44, oral late-breaker: Sterling, et al., The PREVENT TB Study (TB Trials Consortium Study 26): 3 months of once-weekly rifapentine + INH vs. 9 months of daily INH for treatment of latent TB infection: First report of results of a multi-center, randomized clinical trial.

Preliminary trial results suggest that treatment for latent TB infection could soon be easier than ever before

A large, multi-country study of preventive treatment among persons with latent TB infection who are at high-risk for active TB disease found that a shorter and simpler course of treatment was as good at preventing the occurrence of new cases of active TB as the current standard of treatment, and was completed by more patients. Preliminary results of the CDC-sponsored trial were presented today at the 41st Union World Conference on Lung Health in Berlin, Germany.

The study began enrolling volunteers in 2001, and the preliminary analysis included nearly 8,000 people (n=7,846) with latent TB infection at high-risk for active disease. Participants lived in countries with low or medium TB incidence; most participants were located in the U.S. or Canada (approximately 90 percent), with additional participants in Brazil and Spain. The study is a Phase III randomized clinical trial and is the largest trial of TB preventive therapy conducted by the U.S. Public Health Service since the 1960s. It was implemented through the TB Trials Consortium (TBTC), a CDC-funded partnership of domestic and international clinical investigators who conduct research on the prevention and treatment of TB.

Participants were randomized to one of two preventive treatment options – an experimental regimen, using three months of once-weekly rifapentine 900 mg and isoniazid 900 mg (3RPT/INH) given through directly-observed therapy, or a standard treatment regimen using nine months of daily isoniazid 300 mg (9INH) which was self-administered. Participants were followed for 33 months after enrollment.

Researchers found that those in the 3RPT/INH arm had a higher treatment completion rate than the 9INH arm (82 percent vs. 69 percent). Rates of new TB cases were low in both study arms, with 23 total TB cases. Additionally, the 3RPT/INH regimen appeared to be safer; the risk of liver injury was lower among participants in this arm.

Although the current standard of treatment is effective in treating latent TB infection, ensuring that those who need treatment both receive and complete the lengthy nine month standard treatment regimen has been a particular challenge. These results suggest that we may soon be able to treat latent TB infection more easily, helping to ensure that treatment is completed so that high-risk patients do not progress to active disease and spread TB to others.

Further analyses of the data are still being completed, and final results are expected next year. Researchers are particularly interested in conducting analyses among two important subgroups – persons co-infected with HIV, and young children (between the ages of 2 and 11) – to better understand the impact this treatment regimen could have on these populations. Once final results are available, CDC-TBTC and other organizations will discuss how best this information can be put into practice. CDC officials believe that these preliminary results represent the first step in what may ultimately transform the treatment of latent TB infection.